Pat Elflein could face a familiar foe Sunday at Detroit, where the Vikings left guard will have an ample measuring stick regardless of whom he blocks from a talented Lions defensive front. But if it’s Lions defensive end Trey Flowers, Elflein will have a lot to prove since the last time they faced off.

Flowers was a Patriots defensive end then, and Elflein was near the end of his run as Vikings center as quarterback Kirk Cousins was flustered and ineffective in a 24-10 loss last December. One Patriots attack plan had coach Bill Belichick move Flowers directly over Elflein, which led to one sack.

In his sixth start at left guard Sunday, Elflein is preparing for a row of “beasts” in Flowers and defensive tackles Damon Harrison and A’Shawn Robinson, even as the Lions’ 29th-ranked defense has sprung leaks this season. From Lions coach Matt Patricia, a Belichick protégé, Elflein said he is expecting anything, including a revisit of his matchup against Flowers, the 265-pound power rusher who signed a five-year, $90 million deal this spring.

“I’ve seen him play everywhere,” Elflein said of Flowers. “I don’t know the rhyme or reason why, but he’s playing over almost everybody.”

Elflein has played all but one game at left guard this season after the Vikings sought an upgrade at center in rookie first-round pick Garrett Bradbury. A return to his college position, where Elflein started 28 games for Ohio State, remains a work in progress. He is being asked to clean up his footwork and other techniques, according to coach Mike Zimmer, as Elflein has been pegged with a team-worst three sacks allowed in five games, according to Pro Football Focus. He missed the Week 2 loss at Green Bay because of to a knee injury.

Vikings coaches have seen improvement from Elflein since the Sept. 29 loss in Chicago, which was his third game at guard since moving from center, where he started two seasons in Minnesota.

“He’s had some ups and downs, but he’s played pretty good the past couple weeks,” Zimmer said. “It’s a transition to playing that position a little bit. The scheme is new. The footwork is new. It’s not just like you jump in and go.”

Also new is the interior trio of Elflein, Bradbury and guard Josh Kline, who will return to the lineup Sunday after missing last week’s game because of a foot injury.

The Vikings offensive line needs its communication to be seamless against a morphing Lions defensive front. Coaches hope time equals improvement from the interior three, according to coordinator Kevin Stefanski.

He added the offense’s fit remains solid with Elflein, an athletic blocker faring better for the Vikings’ third-ranked rushing attack.

“There’s a ton of effort and finish plays from him,” Stefanski said, “which I think if you go back and watch some of our longer runs, there’s always an offensive lineman finishing, and Pat has been right there leading the charge.

“So, I think he really fits our mentality of what we’re trying to do, and I think just more reps with him and Garrett [Bradbury] next to each other, I think the more the better.”

As Vikings coaches seek some more stability in Elflein and the offensive linemen, one of the biggest stresses ahead of Sunday is the Lions’ unpredictability.

Detroit’s fronts can change week to week and series to series as “they’ll go 3-4, they’ll go four down, they’ll go Bear front [eight men in the box],” said Zimmer.

The Vikings lost to an equally varied defense last December at New England, the one that moved Flowers — now the Lions’ star edge rusher — over Elflein. The Patriots hit the Vikings offense with an array of linebackers wandering, seemingly aimlessly, before the snap to stir up confusion.

It worked against many Vikings, including Elflein; so well that Patricia tried some of the Patriots’ pre-snap movement a couple weeks later during the Vikings’ victory at Detroit last year.

Against the Lions, this version of Elflein and the Vikings offensive line can prove they have learned to hit a curveball against a talented defensive line.

“Similar [to the Patriots] in the fact you don’t know what you’re going to get,” Elflein said. “That’s the carryover. They’re going to have a game plan for you and it’s probably not going to be what they did last week.”

Andrew Krammer covers the Vikings for the Star Tribune, entering his sixth NFL season. From the Metrodome to U.S. Bank Stadium, he's reported on everything from Case Keenum's Minneapolis Miracle, the offensive line's kangaroo court to Adrian Peterson's suspension.